Using a mouse aggravates my RSI. I avoid it. I’ve found with a split keyboard and a natural arm position, I can type for long periods of time with minimal stress. So, I do everything through the keyboard.
I use a few different tools to accomplish this. First, I have a dedicated button on my keyboard for activating Homerow. Homerow lives in my menu bar and, when activated, highlights everything on screen that can be clicked. Type a one-to-three letter combination and Homerow will use the macOS Accessibility APIs to click that button / link / whatever. It sometimes chokes on my external monitor, unfortunately, but it is under active development and improving.
For writing code, I use Visual Studio Code or WebStorm with a Vim extension. This allows me to rapidly navigate and edit text using just the keyboard.
For everything else, I try to use keyboard shortcuts. Nothing fancy, just Cmd-Tab, Ctrl-Tab, that kind of thing. Most well-made apps have keyboard shortcuts to do most things. Mostly. I just try to memorize them as they come up.
I also use Alfred extensively. Alfred is a wonderful little launcher for macOS. It’s great for quickly opening apps and files, but the real gold is in workflows. Alfred lets you trigger complex automations with just a few keystrokes. For example, when I have to join a call, I use a workflow that pauses my music and launches Google Meet. Scripting these common, tedious actions saves significant time (and wear and tear on my wrists).
Lastly, I also try to use the command line. A good terminal window lets you do almost everything, provided you know the right incantation. It’s not user-friendly or discoverable, but it is entirely keyboard-driven.
For anyone interested in this kind of thing, I recommend looking into macOS’s mouse control via head tracking. You can move the mouse by tilting your head and click by sticking out your tongue. One of the coolest accessibility features I’ve ever encountered.